Lance Armstrong wasn't kidding when he said tonight that it's been "a difficult two weeks."

But the embattled athlete, who has been stripped of his seven Tour de France titles under a cloud of doping allegations, tried to maintain some perspective at 15: An Evening at Livestrong, a gala benefiting the cancer-fighting foundation Armstrong founded in 1997.

"I've been better but I've also been worse," he told the assembled party at the Austin Convention Center.

"It's hard to imagine that about a mile from here at Z Tejas [a local restaurant], I sat with five friends 15 years ago. We talked about my diagnosis, my disease, my prognosis. We asked: How could we help and serve people? It was October 1996.

"I said: Let's do a bike ride. Maybe we would raise $1,000. Give it to someone else. But the mission grew."

The Lance Armstrong Foundation—responsible for those yellow Livestrong wristbands that laid the foundation for every other color of cause-supporting wristband out there—has since raised half a billion dollars and touched lives of 2.5 million cancer survivors around the world, according to its founder, who beat stage-four testicular cancer before embarking on his historic cycling run.

"This mission is bigger than me," Armstrong continued. "It's bigger than any individual. Martin Luther King said, 'We must accept finite disappointment but never lose infinite hope.' This team behind me has infinite hope.

"The people in this room have infinite hope. The mission absolutely must go on. We will not be deterred. We will go forward. There's 28 million people around the world who need us. One last request: Let's have a hell of a good time tonight."

It had to have been a bittersweet evening for Armstrong, who resigned as chairman of the foundation this week amid more damning reports about his cycling team's alleged doping practices. He has vowed to remain active behind the scenes.

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